Centrifugal pump



April 29, 1969 N. D. JENSEN CENTRIFUGAL PUMP Sheet Filed Aug. 8. 1967April 29, 1969 JENSEN 3,440,968

CENTRIFUGAL PUMP Filed Aug. s, 1967 Sheet 3 of 2 United States Patent OU.S. Cl. 103-108 4 Claims ABSTRACT OF THE DISCLOSURE Centrifugal pumpwith a tubular pump housing and a guiding device attached therein andconsisting of two skirts and guide vanes lying therebetween, and inwhich all parts are made by punching of sheet material, preferablyStainless steel sheet and welded to each other and, for example, guidedby means of pins and holes. A unit of the said kind is .assembledaxially with similar units with intermediate layers of resilient sealingmeans. Each section of housing and each outer skirt are made of twopieces which are joined, abutting in a plane at right angles to thelongitudinal axis of the housing section and connected by a singlewelded seam extending around the tubular housing in said plane in orderto facilitate the manufacturing of said parts and placing of the guidingdevice in the housing section and further to make possible the use of aninwardly projecting flange on the housing section so as to provide afiat contact surface for a sealing ring.

Background of the invention In pumps hitherto manufactured of this kindthe pump housing section has been drawn up from a fiat sheet and theguiding device has been assembled to form a unit by the Skirts beingwelded to the guide vanes. The said unit has subsequently beenintroduced through one open end of the housing section, which thereforehas to be open With a diameter corresponding to the inner diameter ofthe section, and the guiding device has thereafter been attached in thehousing section by Welding at the end opposite to the end through whichthe device Was introduced and where there is an inwardly projectingflange. Thus, the guiding device is only retained at the said place, andowing to the open end the housing sections cannot be sealed in relationto each other by butt Welding, but by means of telescope joints withsealing means lying between two axial surfaces, which gives no idealsealing by axial assembly.

Summary of the invention The centrifugal pump according to the inventionhas a tubular pump housing composed of several coaxial sections; in eachsection there is attached a guiding device consisting of an outer skirt,an inner skirt and a number of guide vanes mounted therebewteen, all ofthe said parts are made separately by drawing or punching of Sheetmaterial and assembled by means of weiding or, for example, guidingmeans such as pins and holes; the housing sections are joined axiallywith intermediate layers of resilient sealing means, -and the housingsections and the outer Skirts of the guiding devices are each formed oftwo parts abutting to each other in a plane at right angles to thelongitudinal axis of the housing, the said four parts being assembledwith each other by means of -a single welded seam extending around thehousing in the said plane.

By this design various advantages `are obtained. The drawing process bymanufacturing the housing section is facilitated, the height to whichdrawing is performed being reduced to one half, and annealing Operationsmay thus be dispensed with. The guiding device need not as in the knownpumps be welded to form a finished unit before it is mounted in thehousing since the individual parts may be loosely assembled andintroduced into the half section, after which the two section halves andthe parts of the guiding device alike are joined and retained to eachother by a single Welding Connecting the guiding device to the wall ofthe housing, by which a very rigid assembly is provided.

Another advantage obtained is that the parts of the guiding device maybe introduced through the open end of the half section involved, so thateach half section of the housing at the end remote from the welded seammay have an inwardly projecting flange constituting a substantially fiatcontact surface for a sealing ring which is axially compressible betweentwo such flanges. This provides a better sealing than that of telescopeconnections, since an increasing overpressure in the housing sectionwill cause increased compression of the sealing material. The flangesmay readily be manufactured by simple pressing Operations.

An embodiment of a centrifugal pump according to the invention will nowbe described with :reference to the drawing, in which:

FIGURE 1 shows a section through a part of the pump, viewed from theside,

FIGURE 2 a part of FIGURE 1 on a larger scale,

FIGURE 3 an exploded view, showing some of the parts of the guidingdevice, and

FIGURE 4 an exploded view of a pump section with a guiding device, priorto assembly.

FIGURE 1 shows that part of the housing of a centrifugal pump whichcontains two stages, that is, two impellers and two guiding devices. Thehousing of the centrifugal pump is formed of tubular sections, denotedas a whole by `1 and mounted coaxially with each other. Each section isdivided into two half parts 2 joined to each other on a transverse planewhich is indicated by a dash and dotted line 3 in FIGURE 1.

The halves 2 of the housing section are drawn from a fiat blank, and onehalf has a relatively narrow, inwardly projecting flange 4, whereas theother half has a wider, inwardly projecting flange 5. In each housingsection 1 is attached a guiding device, denoted as a whole by 6 andcarrying a bearing 7 for the pump shaft 8 which carries impellers 9, ofwhich only one s indicated in the upper housing section in FIGURE 1;however, there is a corresponding impeller in the lower housing section1 and in the remaining housing sections of the pump. The impeller 9 isattached to the shaft 8 by means of a bushing 10 screwed into a ring 11which is attached to the disc 12 provided on the impeller.

To each flange 5 is welded a ring 13 to form bearing for a sealing ring14 in which the impeller is rotating. Between the flange 4 and theflange 4' is provided a fiat seal 15, and the housing sections 1 areassembled in axial direction by retaining means (not shown), such aslongitudinal bolts.

All parts are made of steel Sheet, preferably Stainless steel, bydrawing or punching.

The manufacture of the pump is illustrated in FIGURES 3 and 4, fromwhich it will be evident that the guiding device 6 consists of an inner,bowl-shaped skirl 16 and an outer bowl-shaped skirt formed of two partsthat is, an upper part 17 and a lower part 18. The twc parts carryoutwardly projecting flanges 19 which face each other, and one part hasa number of holes 20. The inner skirt 16 has two rows of holes 21 and 22whic Similarly as the holes 20 are formed as slits. Between th twoSkirts 16 and 17, 18 are mounted a number of guide 3 vanes 23 providedwith guide webs 24 adapted to be received in the holes 20, 21 and 22.

The two half parts 2 of the housing section are made by drawing from afiat Sheet blank, and owing to their relatively low height thisoperation is easy to perform and annealings may be dispensed with. Fromthe bottom is cut a circular part so as to form the flanges 4 and 5 andcorresponding circular openings 25 and 26. The opposite ends of the halfparts 2 have free edges 27 surrounding an opening corresponding to theinside diameter of the half part. The ring 13, which is likewise made bydrawing, is welded to one half part 2 of the housing section as shown inFIGURE 4.

The parts of the guiding device 6 are assembled separately thereby thatthe guide vanes 23 are mounted on the inner skirt 16, the pins 24 beingpressed into the holes 21 and 22. The pins are adapted to fit rathersnugly and firmly in the holes, when pressed into these, and the lowerhalf 18 of the outer skirt is then mounted, the lower pins 24 of theguide vanes being introduced into the holes 20. Pins and slits have suchan oblique position that the introduction is readily performed by aslight screwing movement of the part 18.

The upper part 17 is then lowered into position over the loosely mountedguide vanes 23 which are formed in such manner as to thereby provide acertain distance between the flanges 19. The combined guiding device issubsequently introduced into the upper half part 2, while the lower halfpart 2 is raised to join the upper one and assembled with the latter bymeans of a suitable tool, by which the flanges 19 are pressed togetherby the edges 27 as illustrated in FIGURE 2, in which the sectionsurrounded by the circle a corresponds to that shown in FIGURE 1 andmarked a. Owing to the guiding device being wedged in this manner, theinterior Casing 16 is subjected to such a strain that it is capable ofsupporting the shaft bearing 7 which is pressure welded in the skirtbefore or after the final assembly. The guiding device is assembled andattached in the housing by means of a single circumferential Weldingwhich includes the edges 27 and the flanges 19 and extends along thedash and dotted line 3 in FIGURE 1. At the upper end the guiding deviceis guided by the tubular part 28 fitting in the opening 26.

The aforesaid circumferential Welding may be performed as electric arcWelding with protective gas, and as filler material may be used theflanges 19. If desired, the flange 19 may be made of a smaller diameterthan the outer diameter of the parts 2 of the housing section so as toform a circumferential groove when assembling, which is then filled withforeign filler material during the welding operation. 4

It will be appreciated from the foregoing description that a safe andstable connection between all parts is obtained 'by means of the Weldingseam referred to so V 4 that by the said single operation there isproduced a rigid pump unit which may be assembled with correspondingunits and in which shaft and impeller may be inserted.

I claim:

1. A centrifugal pump comprising a tubular pump housing including aplurality of coaxial sections, a guiding device in each sectioncomprising an outer skirt, an inner skirt and a number of guide vanesbetween said skirts, said skirts, guide vanes and sections beingconstituted of sheet material assembled together, guiding means betweensad inner skirt and said vanes for engaging the same together,intermediate layers of resilient sealing means clamped between adjacentcoaxial sections, each housing section being constituted of two coaxialportions and the outer skirt of each guiding device including two partswith abutting annular surfaces disposed in a plane at right angles tothe longitudinal axis of the housing, said annular surfaces beingclamped between adjacent edges of said coaxial portions, and a singleweld seam extending around the housing in said plane of the abuttingflanges to join the same and said edges of said coaxial portions.

2. A pump as claimed in claim 1 wherein each coaxal portion of thehousing section includes, at the end remote from the welded seam, aninwardly projecting flange constituting a substantially fiat contactsurface for the sealing means which is clamped between two such flanges.

3. A pump as claimed in claim 2 wherein each said outer skirt includes,at one end, an annular part which is adapted to be received in anopening formed by the inner edge of said inwardly projecting flange ofthe associated coaxial portion of the housing section, the inner skirtadjacent said annular part having an opening and a bearing, attached tosaid inner skirt in said opening, for a pump shaft.

4. A pump as claimed in claim 1 wherein the two parts of the outer skirtinclude outwardly projecting flanges at their abutting surfaces, saidflanges being wedged between the adjacent edges of said coaXial portionsand united thereto by said weld scam.

References Cited UNITED STATES PATENTS 2,007,954 7/ 1935 Carlson 103-1142,598,620 5/1952 Swift.

2,753,807 7/ 1956 Lung 103-108 F OREIGN PATENTS 1,016,097 1/1966 GreatBritain.

HENRY F. RADUAZO, Primary Examiner.

U.S. CI. X.R. 103 102, 111,

